With only two more weeks left in the season, it's not worth risking Mariota's long-term development to trot him out with a bad knee on a 3-11 team.

Although the Titans had a rough season, Mariota has had an impressive rookie season. In 12 games, Mariota threw for over 2,800 yards with a 62% completion percentage, 19 touchdowns, and 10 interceptions. Among the highlights of his season was a perfect NFL-debut, throwing 209 yards on a 87% completion rate, four touchdowns, and no interceptions with a perfect 158.3 passer rating. He also rattled off an 87-yard rushing touchdown in Week 13, the longest of quarterbacks this season.

Titans backup quarterback Zach Mettenberger is expected to start the last two games of the season.